Electric motor-driven mechanism

ABSTRACT

An electric-motor drive mechanism is proposed, with an electric motor ( 12 ) that has a brush holder ( 16, 116, 216 ) for containing brushes ( 15   a   , 15   b ) and at least one magnetic field sensor ( 18   a   , 18   b   , 118   a   , 218   a ) for detecting the magnetic field of a magnetic wheel ( 19 ) non-rotatably connected to the motor armature shaft ( 32 ) and an electronics housing ( 20 ) for containing an electronics mounting plate ( 24 ) for a set of motor output and/or control electronics. The electronics mounting plate ( 24, 124, 224 ) is disposed outside an electric motor pole pot housing ( 26 ) on a support ( 28, 128, 228 ) formed onto the brush holder ( 16, 116, 216 ) and that the at least one magnetic field sensor ( 18   a   , 18   b   , 118, 218 ) directly contacts the control electronics on the electronics mounting plate ( 24, 124, 224 ) by means of first inserted strip conductors ( 30   a - 1 . . . 30   a - 3, 30   b - 1 . . . 30   b - 3, 130, 230 ) that are guided in bundles and are at least partially integrated into the brush holder ( 16, 116, 216 ).

The invention relates to an electric-motor drive mechanism according tothe preamble to the main claim.

The reference DE 43 37 390 C2 has disclosed an electric-motor drivemechanism with an electronic module which has a circuit for supplyingpower to the electric motor of the drive mechanism. The brush guide of acommutation device of the electric motor is connected to a supportingcomponent of the electronic module constituted by an electric chassis.The supply of power to the brushes of the commutation device takes placeby means of strip conductors, which are not a component of a printedcircuit board of the electronic module.

Furthermore, electric-motor drive mechanisms with brush holders havebeen disclosed, which has a plug housing with connector plugs formedonto it. The brush holders are disposed inside the electric motor of thedrive mechanism. Printed circuit boards with Hall sensors are disposedon the brush holders and are supplied with energy via inserted stripconductors that electrically contact the connector plugs.

This apparatus has the disadvantage that the attachment of printedcircuit boards to the commutator is costly from a technicalmanufacturing standpoint and the printed circuit boards can only bereplaced with difficulty in the event of the defect. Furthermore, theelectronic components on the printed circuit board are subjected to therough environmental conditions inside the motor. On the one hand, thetemperature inside the motor is increased, on the other hand abrasion ofthe carbon brushes, the armature shaft bearing, or the armature shaftitself produced by the motor operation can come to bear on theelectronic components and can trigger malfunctions and short-circuits.

ADVANTAGES OF THE INVENTION

The invention, with the features of the main claim, has the advantagethat a set of motor control and output electronics, with the exceptionof one or several magnetic field sensors, is disposed completely outsidethe electric motor. Since the magnetic field sensors are not disposed onthe electronics mounting plate as in the previously disclosedembodiments, the tolerances that must be maintained in the installationof the electronics mounting plate are less critical than in thepreviously disclosed embodiments. Furthermore, a modular design ispossible since different control electronics can be provided for thesame motor on different electronics mounting plates without changing themotor concept and a new set of electronics can be installed by replacingthe electronics mounting plate. If the electronics mounting plate isdisposed outside the motor compartment, it is considerably betterprotected against the abrasion of the electric motor. In particular,Hall sensors or magnetoresistive sensors are used as the magnetic fieldsensors.

The term inserted strip conductors is understood to mean that thesestrip conductors are not components of a printed circuit board. Instead,they are used to produce the contact between a printed circuit board andan electronic component that is spaced apart from it. They arecomprised, for example, of metal strips which can constitute separatecomponents or can be applied to other components of the electric motor.

Advantageous improvements and updates of the invention ensue from thedependent claims.

The electric-motor drive mechanism according to the invention can beproduced in a particularly inexpensive manner if the electronicsmounting plate has an essentially rectangular outline. In this case,standard printed circuit boards can be used. It is no longer necessaryto expensively design the outline of the printed circuit boards based onthe contour of the pole pot housing. Smaller deviations from therectangular form can be simply and inexpensively manufactured.

In a favorable embodiment, the electronics mounting plate is disposedlateral to the rotation axis of the motor armature shaft. Thisdisposition is particularly space-saving since the electronics housingcan then turn out to be small.

The pole pot housing of electric motor is advantageously sealed inrelation to the electronics mounting plate. As a result of this measure,the electronics mounting plate is even better protected against theabrasion of the electric motor. Also, moisture and other substances areeffectively prevented from penetrating into the electric motor.

If the support tapers at the transition to the brush holder and theinserted strip conductor(s) are integrated into the taper, then they areguided from the pole pot housing to the electronic mounting plate sothat they are protected in relation to the outside without additionalmeasures. In addition to the mechanical protection, the accommodation inthe brush holder/support, also effectively protects them electrically.By means of the taper between the support and the brush holder, thesupport can move the electronics mounting plate elastically out of theway within certain limits when there are forces engaging the outside ofthe electronics housing, as a result of which the danger of breakage isreduced.

In one embodiment of the invention, two magnetic field sensors areprovided and the brush holder and the support have an at leastapproximate reflective axis lateral to the axis of the motor armatureshaft in the plane of the electronics mounting plate. The magnetic fieldsensors are disposed in the circumference direction in relation to themagnetic wheel at approximately equal angles in relation to the centerpoint of the magnetic wheel and the reflective axis. The use of twospeed sensors permits the determination of the rotation directionthrough evaluation of the phase shift of the sensor signals. On thewhole, this embodiment has the advantage that the inserted stripconductors can be disposed in a particularly space-saving manner.

The space-saving disposition can be further improved if the at least onemagnetic field sensor is disposed tangential to the edge of a recess ofthe brush holder for containing the magnetic wheel, the inserted stripconductors have contact ends to the magnetic field sensor that aredisposed oriented toward the brush holder, and contact strips of theinserted strip conductors are guided between the contact ends and theelectronics mounting plate from the edge of the recess to the edge ofthe brush holder and from the edge of the brush holder onward, extendessentially parallel to the contour of the brush holder or the supportand parallel to the plane of the electronics mounting plate. By means ofthis special guidance of the inserted strip conductors, moreover, themechanical stability of the brush holder/support is improved and thebreakage susceptibility is reduced since the strip conductors constitutea skeleton-like support structure inside the brush holder and thesupport. As a result of their parallel routing, the electrical signalstransmitted from them are less susceptible to incoming interferencesignals.

Another advantageous improvement is achieved if second inserted stripconductors for supplying power to the brushes are at least partiallyintegrated into the brush holder and are disposed between the supportand the brush holder. In this instance, separate electrical routingsfrom the electronics housing into the motor are no longer necessarysince all of the contact strips to the motor extend inside the brushholder or the support.

Further advantageous improvements and updates of the invention ensuefrom the other dependent claims and in conjunction with the subsequentdescription.

DRAWINGS

FIG. 1 shows a partially sectional detail of an electric-motor drivemechanism according to the invention,

FIG. 2 is a view of the drive mechanism according to FIG. 1, in thedirection II in FIG. 1,

FIG. 3 shows a section through a second exemplary embodiment of thebrush holder with a support injection molded onto it, which can be usedin an electric-motor drive mechanism according to FIG. 1 as analternative to the brush holder shown there, and

FIG. 4 is a perspective representation of a third exemplary embodimentof a brush holder for an electric-motor drive mechanism according to theinvention.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1 shows an exemplary embodiment of the electric-motor drivemechanism according to the invention. An electric-motor drive mechanism10 is comprised of an electric motor 12 and a transmission attached toit, which is not shown in detail. The electric motor 12 has a brushholder 16 for containing brushes 15 a, 15 b (FIG. 2) and two Hallsensors as magnetic field sensors 18 a and 18 b, which cooperate with amagnetic wheel 19 non-rotatably fastened to a motor armature shaft 32 inorder to determine the rotation of the motor armature shaft 32 inrelation to the stator of the electric motor 12 and values derived fromthis. The motor armature shaft 32 reaches through a recess 21 of thebrush holder 16. The magnetic wheel 19 and a commutator 29, which islikewise disposed on the motor armature shaft 32 and is supplied withcurrent for the electric motor 12 via the brushes 15 a, 15 b, can freelyrotate in the recess 21. The outer contour 17 of the brush holder 16 isessentially inserted into the inner contour 25 of the pole pot housing26. With the exception of the formed-on projection 27, which aids in thefixing of the brush holder 16 in the pole pot housing 26 and a likewiseformed-on support 28, the brush holder 16 is accommodated completelyinside the pole pot housing 26 or a transmission housing 36.

An electronics housing 20 for containing and protecting an electronicsmounting plate 24 is disposed on the drive mechanism 10. The electronicsmounting plate 24 is contacted with a plug connector in a plug part, notshown, that is formed onto the electronics housing 24 and supports a setof motor output and control electronics. Its outline is essentiallyrectangular in shape. The electronics mounting plate 24 is disposedlateral to the rotation axis of the motor armature shaft, i.e. with itsplanar normals parallel to the rotation axis, outside the pole pothousing 26 and is supported by a support 28 that is formed onto thebrush holder 16 and whose outline is only slightly larger than that ofthe electronics mounting plate 24. By means of groups 30 a and 30 b eachcomposed of three inserted strip conductors 30 a-1 . . . 30 a-3 and 30b-1 . . . 30 b-3, both magnetic field sensors 18 a and 18 b areelectrically connected to the control electronics on the electronicsmounting plate 24. They are comprised of buckled and/or offsetbent/stamped sheet metal parts and protrude from the support 28 or thebrush holder 16 only at their ends for contacting and are otherwisecompletely injection molded into the brush holder 16 or the support 28.

In the transition region to the brush holder 16, the support 28 has ataper 34 (FIG. 2). Seals are disposed around the taper 34, which sealthe support 28 with the electronics mounting plate 24 on one hand inrelation to the transmission housing 36 and on the other hand inrelation to the pole pot housing 26. The inserted strip conductors 30a-1 . . . 30 a-3 and 30 b-1 . . . 30 b-3 are guided through the interiorof the taper 34 as a passage region. The electronics mounting plate 24itself is consequently completely sealed in relation to the pole pothousing 26.

The magnetic field sensors 18 a and 18 b are disposed at an angle ofapproximately 90° in the circumference direction in relation to thecircular recess 21 and the magnetic wheel 19, which is disposedconcentric to the recess 21 and axially symmetrical to an axis 38 of thebrush holder 16. The axis 38 essentially constitutes a reflective axisof the brush holder 16 and of the support 28 and intersects with therotation axis of the motor armature shaft 32. The two groups 30 a and 30b of inserted strip conductors 30 a-1 . . . 30 b-3 are disposed at thesame distance from the reflective axis 38 and their projections onto theplane of the electronics mounting plate 24 are virtually axiallysymmetrical to each other. All of the inserted strip conductors 30 a-1 .. . 30 b-3 in the exemplary embodiment extend essentially parallel tothe plane of the drawing in FIG. 2, but are disposed partially offset toone another in the axial direction (perpendicular to the plane of thedrawing of FIG. 2).

An alternative embodiment of the brush holder 116 for the drivemechanism 10 according to FIG. 1 is shown in FIG. 3. In this instance,the Hall sensor 118 a is likewise contacted by inserted strip conductors130 a-1 . . . 130 a-3. On their ends remote from the Hall sensor 118 a,the inserted strip conductors 130 a-1 . . . 130 a-3 also have contactingmeans 150 a-1 . . . 150 a-3 for connection to plug connections which canbe used, for example, to connect to a set of external electronics butare also simultaneously contacted by the electronics mounting plate 124.The inserted strip conductors 130 a-1 and 130 a-3 are each comprised ofa stamped sheet metal part 152 a-1 and 152 a-3 as well as sections ofconductive material 154 a-1 and 154 a-3 that are applied in an inlaidfashion into the surface of the plastic material of the brush holder116. The application can be carried out, for example, using the MIDtechnique. The sections 154 a-1 and 154 a-3 are inserted stripconductors in the sense that they are not a component of a printedcircuit board, but are applied directly to the plastic brush holder 116that is produced during the injection molding process.

A third embodiment of the brush holder 216 for an electric-motor drivemechanism according to the invention is shown in a perspectiverepresentation in FIG. 4. The inserted strip conductors 230 a, 230 b inthis instance are one-piece stamped parts with contact ends 240 a, 240and contact strips 242 a, 242 connected to them with an essentiallyrectangular cross section, which are injection molded into the brushholder 216. The axial offset of the inserted strip conductors on thesupport end is executed so that the inserted strip conductors 230 a, 230a, and 230 b, 230 b are contacted by the top or the bottom ofelectronics mounting plate 224 depending on their axial position. Bymeans of the contact ends 240 a, 240 b, these inserted strip conductorselectrically contact the Hall sensors, which are preferably embodied asICs. The contact strips 242 a, 242 b are placed in the brush holder 216and in the support 228 so that they are routed from the magnetic fieldsensors to the edge of the brush holder 216 and extend from the edgeessentially parallel to the outer contour 217 of the brush holder 216,parallel to the contour of the taper 234 in the transition regionbetween the brush holder 216 and the support 228.

Furthermore, second inserted strip conductors 244 a and 244 b areintegrated into the brush holder 216 and the support 228 which, on thesupport 228 side, are connected to the electronics mounting plate 224and on the brush holder side 216, are connected to the brushes of theelectric motor. The brushes are supplied with current via the secondinserted strip conductors 244 a and 244 b They likewise extend in anaxially symmetrical manner in relation to the reflective axis 238 and—atleast on the side of the brush holder 216—are disposed in the centerbetween the groups 230 a and 230 b of the first inserted stripconductors.

What is claimed is:
 1. An electric-motor drive mechanism with an electric motor (12) that has a brush holder (16, 116, 216) for containing brushes and at least one magnetic field sensor (18 a, 18 b, 118, 218) for detecting the magnetic field of a magnetic wheel (19) non-rotatably connected to the motor armature shaft (32) and an electronics housing (20) for containing an electronics mounting plate (24, 124, 224) for a set of motor output and/or control electronics, wherein the electronics mounting plate (24) is disposed outside an electric motor pole pot housing (26) on a support (28, 128, 228) formed onto the brush holder (16, 116, 216), characterized in that the at least one magnetic field sensor (18 a, 18 b, 118, 218) directly contacts connection points of the control electronics on the electronics mounting plate (24, 124, 224) by means of first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1, 130, 230) that are guided in bundles and are at least partially integrated into the brush holder (16, 116, 216), wherein the first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1 . . . 30 b-3, 130, 230) which respectively contact the same magnetic field sensors (18 a, 18 b, 118 a, 218 a) extend essentially parallel to one another, wherein the magnetic field sensors (218, 218 b) are disposed tangentially to the edge of a recess (221) of the brush holder (216) in order to receive the magnetic wheel (19), that the first inserted strip conductors (230 a, 230 a, 230 b, 230 b) have contact ends (240 a, 240, 240 b, 240 b) to the magnetic field sensor (128 a, 218 b) that are disposed oriented toward the brush holder, that contact strips (242 a, 242 a, 242 b, 242 b) of the first inserted strip conductors (230 a, 230 a, 230 b, 230 b) are guided between the contact ends (240 a, 240, 240 b, 240 b) and the electronics mounting plate (224) from the edge of the recess (221) to the edge of the brush holder (216) and from the edge of the brush holder (216) onward, extend essentially parallel to the contour of the brush holder (216) or the support (228) and parallel to the plane of the electronics mounting plate (224).
 2. The electric-motor drive mechanism according to claim 1, characterized in that the first inserted strip conductors (30 a-1 . . . 230 a-3, 30 b-1 . . . 230 b-3, 130, 230) in the brush holder (16, 116, 216) are disposed offset to the rotation axis of the motor armature shaft (32) and parallel to the plane of the brush holder (16, 116, 216) or of the support (28, 128, 228).
 3. The electric-motor drive mechanism according to claim 2, characterized in that depending on their axial position on the side of the electronics mounting plate (224), the individual first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1 . . . 30 b-3, 130, 230) are contacted by the top side or the bottom side of the electronics mounting plate (224).
 4. An electric-motor drive mechanism with an electric motor (12) that has a brush holder (16, 116, 216) for containing brushes and at least one magnetic field sensor (13 a, 18 b, 118, 218) for detecting the magnetic field of a magnetic wheel (19) non-rotatably connected to the motor armature shaft (32) and an electronics housing (20) for containing an electronics mounting plate (24, 124, 224) for a set of motor output and/or control electronics, wherein the electronics mounting plate (24) is disposed outside an electric motor pole pot housing (26) on a support (28, 128, 228) formed onto the brush holder (16, 116, 216), characterized in that the at least one magnetic field sensor (18 a, 18 b, 118, 218) directly contacts connection points of the control electronics on the electronics mounting plate (24, 124, 224) by means of first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1, 130, 230) that are guided in bundles and are at least partially integrated into the brush holder (16, 116, 216), wherein the inserted strip conductors (30 a-1 . . . 30 a-3 . . . , 30 b-1 . . . 30 b-3, 130, 230) are sheet metal parts selected from the group consisting of buckled parts, offset bent parts and stamped parts and protrude from an element selected from the group consisting of the support (28, 128, 228) and the brush holder (16, 116, 216) only at their ends for contacting and are otherwise completely injection molded into the elements selected from the group consisting of the brush holder (16, 116, 216) and the support (28, 128, 228).
 5. The electric-motor drive mechanism according to 4, characterized in that the electronics mounting plate (24, 124, 224) has an essentially rectangular outline.
 6. The electric-motor drive mechanism according to claim 4, characterized in that the electronics mounting plate (24, 124, 224) is disposed lateral to the rotation axis of the motor armature shaft (32).
 7. The electric-motor drive mechanism according to claim 4, characterized in that the pole pot housing (26) and/or the transmission housing (36) of the drive mechanism (10) are sealed in relation to the electronics mounting plate (24, 124, 224).
 8. The electric-motor drive mechanism according to claim 4, characterized in that in the transition to the brush holder (16, 116, 216), the support (28, 128, 228) has a taper (34, 234) and that the first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1 . . . 30 b-3, 130, 230) are integrated into the taper (34).
 9. The electric-motor drive mechanism according to claim 8, characterized in that two magnetic field sensors (18 a, 18 b, 118, 218) are provided, that the brush holder (16, 116, 216) and the support (28, 128, 228) have an at least approximate reflective axis (38) lateral to the rotation axis of the motor armature shaft (32) in the plane of the electronics mounting plate (24, 124, 224), and that the magnetic field sensors (18 a, 18 b, 118, 218) are disposed in the circumference direction in relation to the magnetic wheel (19) at approximately equal angles in relation to the center point of the magnetic wheel and the reflective axis (38).
 10. The electric-motor drive mechanism according to claim 9, characterized in that a group (30 a, 30 b, 130 a, 130 b, 230 a, 230 b) of first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1 . . . 30 b-3, 130, 230) is guided to each of the two magnetic field sensors (18 a, 18 b, 118, 218), and that the groups (30 a, 30 b, 130 a, 130 b, 230 a, 230 b) are disposed virtually symmetrical to each other in their projections onto the plane of the electronics mounting plate (24, 124, 224) in relation to the reflective axis (38).
 11. The electric-motor drive mechanism according to claim 4, characterized in that the first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1 . . . 30 b-3, 130, 230) which are respectively contact the same magnetic field sensors (18 a, 18 b, 118 a, 218 a) extend essentially parallel to one another.
 12. The electric-motor drive mechanism according to claim 4, characterized in that second inserted strip conductors (244 a, 244 b) for supplying power to the brushes are at least partially integrated into the brush holder (216) and are disposed between the support (228) and the brush holder (216).
 13. The electric-motor drive mechanism according to claim 12, characterized in that the second inserted strip conductors (244 a, 244 b) for supplying power to the brushes are disposed in the center between the groups (230 a, 230 b) of first inserted strip conductors.
 14. The electric-motor drive mechanism according to claim 4, characterized in that the brush holder (16, 116, 216) is comprised of plastic and the first inserted strip conductors (30 a-1 . . . 30 a-3, 30 b-1 . . . 30 b-3) are at least partially injection molded onto into the brush holder (16, 116, 216).
 15. The electric-motor drive mechanism according to claim 4, characterized in that the first inserted strip conductor (130 a-1 . . . 130 a-3, 130 b-1 . . . 130 b-3) are at least partially comprised of sections (154 a-1, 154 a-3) of conductive material that is applied to the surface of the brush holder.
 16. The electric-motor drive mechanism according to claim 4, characterized in that on their side remote from the at least one magnetic field sensors (118 a), the first inserted strip conductors (130 a-1 . . . 130 a-3) have contacting means (150 a-1 . . . 150 a-3) for connecting to plug connections.
 17. The electric-motor drive mechanism according to claim 4, characterized in that at least one of the magnetic field sensors (18 a, 18 b) is welded and/or soldered to the inserted strip conductors (30 a-1 . . . 30 a-3 or 30 b-1 . . . 30 b-3) that connect it to the control electronics. 